System CPU Usage

What does the System CPU usage mean?

I recently downloaded a widget for my dashboard that monitors CPU usage. I was surprised to find that most of the time the CPU usage was right up at 100% being split about 40-60 between "User" and "System" respectively with 0-2% designated as "Idle". Does this mean that my processor is maxing out all the time? I have a 1.33 GHz PowerPC G4 with 1GB DDR SDRAM, and it seems to be running fine.

I would have expected to see most of my CPU usage percentage being designated as idle, as I can't imagine I am using more than 40% very often. What does it mean when it says that "System" is taking up most of my CPU power?
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jfredricksonAsked:
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brettmjohnsonConnect With a Mentor Commented:
Background processes use CPU resources when the system is not doing anything else.  They yield the CPU to the foreground processes when you use the keyboard or mouse.
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brettmjohnsonCommented:
Mac OS X 10.4 Spotlight indexer runs in the background.  If you have rapidly changing files in the file system (or a freshly mounted filesystem that has not been indexed yet), Spotlight will be doing its job in the background.  Safari, too, can consume copious CPU time - usually animating large numbers of ads [thank heaven for Pith Helmet].

You can see what processes are consuming CPU cycles by running the command 'top' from the command line, or the GUI version, "/Applications/Utilities/Activity Monitor.app"



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jfredricksonAuthor Commented:
So when the "User" and "System" usage is up near 100% it means that the processor is actually being used 100%? Why am I not then seeing any real slowdown in application speed?
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jfredricksonAuthor Commented:
Ahh, that makes sense. What a genius design :)
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